Enzymes behave as biocatalysts, regulating many of the chemical reactions that naturally occur in living organisms. When isolated, enzymes also have many industrial, as well as medical uses. For instance, enzymes are used in the tanning, food and detergent industries.
Much research has been conducted on methods to precipitate enzymes. For instance, Chiang, Alter, and Sternberg, "Purification and Characterization of a Thermostable Alpha-Amylase from Bacillus licheniformis", Starke, Vol. 31, No. 3, pages 86-92, (1979) disclose ammonium sulfate precipitation of TAKA-THERM.RTM., a trademark of Miles Laboratories, Inc., Elkhart, Ind. for carbohydrase enzymes. In this reference, the TAKA-THERM used was alpha-amylase isolated from Bacillus licheniformis BLM 1777. The precipitation was followed by cellulose chromatography purification. Next, fractions were combined and concentrated by ultrafiltration. The enzyme concentrate was then dialized and then ammonium sulfate was added until turbidity (the beginning of precipitation) occurred.
Dixon et al., "Enzymes", Academic Press, 3rd edition, pages 1-40, (1979) discuss ammonium sulfate crystallization of enzymes and a variation of this method involving extracting a small amount of the precipitated enzyme with cold, dilute ammonium sulfate solutin.
Yokoyama et al., "Production and Crystallization of Acid Carboxypeptidase of Penicillium janthinellum and Mode of Action on Peptides and Proteins, and Anti-Inflammatory Activities of the Enzyme", Amino Acid Nucleic Acid, Vol. 35, pages 64-75 (1977) discuss combining column chromatography with ammonium sulfate precipitation for recovery of acid carboxypeptidase.
Uwajima et al., "Production, Purification and Crystallization of Creatinine Deiminase of Corynebacterium lilium", Studies on Creatinine Metabolism by Microorganisms, Part II, Tokyo Research Laboratory, Kyowa Hakko Kogyo Company, Ltd., Machida-shi, Tokyo, Agric. Biol. Chem., 41(2) (1977) pages 339-344 disclose a method to obtain crystallized creatinine deiminase consisting of ammonium sulfate fractionation, protamine treatment, and cellulose chromatography.
Uwajima et al., "Production, Purification and Crystallization of III Alpha-Hydroxysteroid Dehydrogenase of Pseudomonas Putrida", Tokyo Research Laboratory, Kyowa Hakko Kogyo Company, Ltd., Machida-shi, Tokyo, Agric. Biol. Chem., Vol. 42, No. 8, pages 1577-1583, (1978) disclose a method to obtain dehydrogenase involving fractionation with ammonium sulfate and column chromatography on DEAE-cellulose, Sephadex G-100 and hydroxylapatite.
McCary in U.S. Pat. No. 3,642,582 discloses a process to obtain alpha-amylase involving first removing polyvalent anions from alpha-amylase preparations, and then contacting the preparation with fibrous alumina.